A Urease-Containing Fluorescent Hydrogel for Transient Information Storage

The improper handling of decrypted information can lead to the leakage of confidential data. Thus, there is increasing interest in the development of self-erasing decrypted data. Herein, we report a urease-containing fluorescent hydrogel for multistage information security protection. Information can be input into the fluorescent hydrogel, which is based on the protonated 4-(N,N-dimethylaminoethylene) amino-N-allyl-1,8-naphthalimide (DEAN-H⁺) and doped with urease, using metal ions, such as Zn²⁺ that coordinate with DEAN. Upon exposure to urea, urease produces NH₃, which reduces the fluorescence of the hydrogel. In the presence of urea, metal-coordinated hydrogel fluorescence decreases more slowly than the fluorescence of the hydrogel alone, revealing the information. The displayed information is then automatically erased within a few minutes. This work opens up a new insights in designing and fabricating information storage materials.